Sounds like it may be due to the jet stream wandering around again.
Sacramento River salmon take a dive
Fishery management officials, surprised by the decline, expect Valley chinook to rebound.
By Matt Weiser - Bee Staff Writer
Published 12:00 am PST Saturday, March 3, 2007
Fall-run chinook salmon that make a home in the Sacramento River and its tributaries fell last year to their lowest numbers since 1992, according to estimates by the Pacific Fishery Management Council.
This is a surprise to fisheries managers, because the population was expected to be strong after commercial fishing was drastically curtailed last year to protect Klamath River fish. The rebound for Klamath salmon is likely to mean better fortunes for Pacific coast commercial fishermen this year.
But now the troubled Sacramento River salmon are the center of attention.
That population includes American River fall-run chinook, and only 8,728 salmon returned to the Nimbus Hatchery on the river last fall, according to the state Department of Fish and Game. That's the smallest number since 1997, well below the 2005 return of 22,349 fish.
The fishery council meets in Sacramento next week to draft plans for the commercial salmon season, which starts May 1.
The decline in Sacramento River fish is not drastic enough to trigger fishing restrictions. But it remains a mystery.
"We're looking at it and wondering what's going on," said Allen Grover, a fisheries biologist at Fish and Game who monitors salmon. "I think it is a little bit worrisome."…
….A clue to the Sacramento River salmon decline emerged in a study published last week by the National Academy of Sciences. It documents a broad decline in Pacific Ocean food sources. Lead author John Barth, an oceanography professor at Oregon State University in Corvallis, said the cause was a southern shift in the jet stream in spring 2005.
That current of winds normally drives a deep upwelling in the ocean off Oregon and Washington that feeds the food chain. But the jet stream blew over California instead, disrupting ocean currents and causing a population decline among mussels and barnacles that feed on plankton.
